Aromatic polycarbonate end capped with maleimide moiety

ABSTRACT

An aromatic polycarbonate containing at least one terminal group represented by the formula ##STR1## wherein R and R&#39; are the same or different and are alkyl, aryl or halogen; a and b are the same or different and are zero or an integer of one to four; W is O, S, SO, SO 2 , CH 2 , CHR or CR 2  wherein R is identified above; 
     X=O, ##STR2##  arylO, or ##STR3## Preferably a and b are the same or different and are zero or one, more preferably each is zero. W is CH 2 , CHR or CR 2 .

This is a division of copending application Ser. No. 232,032, filed8/15/88 now U.S. Pat. No. 4,933,425.

BACKGROUND OF THE INVENTION

The importance of endcapping or terminating polycarbonates with certainend or terminal groups is well known. Polycarbonates which are not soendcapped are generally insufficiently heat stable since the freephenolic end groups provide reactive sites which are generallydetrimental to the thermal stability of the polycarbonate. Well knownand conventionally used endcapping agents include phenol compounds suchas paratertiary butyl phenol, Chroman-I, paracumylphenol, and phenolitself The prior art also discloses other types of compounds that areeffective endcapping agents for the carbonate polymers These endcappingagents include the alkyl phenols disclosed in U.S. Pat. No. 4,269,964and Japanese patent publication number 34992/76; the alkenyl aminesdisclosed in U.S. Pat. No. 3,085,992; the amides disclosed in U.S. Pat.No. 3,399,172; aniline and methylaniline as disclosed in U.S. Pat. No.3,275,601; and the primary and secondary amines disclosed in U.S. Pat.No. 4,001,184. Other endcapping agents described in the prior artinclude the aromatic amines disclosed in U.S. Pat. No. 3,028,365; andthe ammonium compounds, ammonia, primary cycloalkyl amines, and primaryaliphatic or alkyl amines disclosed in U.S. Pat. No. 4,111,910.

Various functionalized phenyl maleimides have been used to controlpolyamide molecular weight. These resins are claimed to be useful inultraviolet crosslinkable compositions, see U.S. Pat. No. 4,645,822,assigned to Bayer. In existing maleimide capped resins, the highlyreactive maleimide group is left exposed after isolation of resin. It islikely that many of the unsaturated end groups will react even beforethe polymer melts. In addition, the maleimide grouping is relativelytoxic and therefore handling of the material is somewhat restrictive.

A novel material has been discovered which bypasses the above problems Amasked maleimide endcapped polycarbonate is prepared from thesubstituted phenolic chain capping material This material is extremelystable and not abnormally toxic at room temperature. However, whenheated to relatively high temperaures as in an extruder, the maskingportion of the molecule is cleaved, therefore leaving the maleimideendcapped polycarbonate available for further reaction with itself orwith other polymer systems thereby providing a new route to novelcopolymers through a melt grafting process.

SUMMARY OF THE INVENTION

In accordance with the invention there is a polycarbonate containing atleast one terminal group represented by the formula ##STR4## wherein Rand R' are the same or different and are alkyl, aryl or halogen, a and bare the same or different and are zero or an integer of one to four. Wis 0, S, SO, SO.sub. 2, CH.sub. 2, CHR or CR.sub. 2 wherein R isidentified above. ##STR5## ##STR6##

Preferably a and b are the same or different and are zero or one, morepreferably each is zero. W is preferably CHR, CH.sub. 2 or CR.sub. 2.

Another aspect of the invention is a composition of the formula ##STR7##wherein R, R', a, b and W are as defined above Y is OH; CR.sup. 2.sub.2COOH wherein each R.sup. 2 is independent and hydrogen, alkyl of one tosix carbon atoms, inclusive; COR.sup. 3 wherein R.sup. 3 is chloro,bromo or hydroxy; arylCOOH; or arylOH.

DETAILED DESCRIPTION OF THE INVENTION

Polycarbonates which can be endcapped with the novel phenolic chainterminating agent of Formula II may be conveniently prepared by a numberof different well known conventional methods One of these methodsincludes introducing an endcapping or chain terminating amount of atleast one compound of Formula II into the polymer forming reaction asone of the reactants. These polycarbonate reactions are well known inthe art and include such conventional processes as the interfacialpolymerization reaction, the pyridine process, and melt polymerizationIn general these reactions involve reacting at least

(1) a dihydric phenol;

(2) a carbonate precursor; and

(3) an endcapping amount of at least one endcapping agent of Formula II.

The high molecular weight aromatic polycarbonate resins are well knowncompounds which are described along with methods for their preparationin interalia in U.S. Pat. Nos. 3,989,672; 3,275,601 and 3,028,365, allof which are incorporated herein by reference.

They may be conveniently prepared by the reaction of at least onedihydric phenol and a carbonate precursor. The dihydric phenols employedin the practice of this invention are known dihydric phenols which maybe represented by the general formula ##STR8## wherein:

R.sup. 1 is independently selected from halogen, monovalent hydrocarbon,and monovalent hydrocarbonoxy radicals;

R.sup. 2 is independently selected from halogen, monovalent hydrocarbon,and monovalent hydrocarbonoxy radicals;

A is selected from divalent hydrocarbon radicals, ##STR9##

n' and n" are independently selected from integers having a value offrom 0 to 4 inclusive; and

y is either zero or one.

The monovalent hydrocarbon radicals represented by R.sup. 1 and R.sup. 2include the alkyl, cycloalkyl, aryl, aralkyl, and alkaryl radicals.

The preferred alkyl radicals are those containing from 1 to about 12carbon atoms. The preferred cycloalkyl radicals are those containingfrom 4 to about 8 ring carbon atoms. The preferred aryl radicals arethose containing from 6 to 12 ring carbon atoms, i.e., phenyl, naphthyl,and biphenyl. The preferred aralkyl and alkaryl radicals are thosecontaining from 7 to about 14 carbon atoms.

The preferred halogen radicals represented by R.sup. 1 and R.sup. 2 arechlorine and bromine.

The monovalent hydrocarbonoxy radicals may be represented by the generalformula --OR.sup. 3 wherein R.sup. 3 has the same meaning as R.sup. 1and R.sup. 2. The preferred hydrocarbonoxy radicals are the alkoxy andthe aryloxy radicals.

The divalent hydrocarbon radicals represented by A include the alkylene,alkylidene, cycloalkylene, and cycloalkylidene radicals. The preferredalkylene radicals are those containing from 2 to about 30 carbon atoms.The preferred alkylidene radicals are those containing from 1 to about30 carbon atoms. The preferred cycloalkylene and cycloalkylideneradicals are those containing from 6 to about 16 ring carbon atoms.

Some illustrative non-limiting of suitable dihydric phenols include:

2,2-bis(4-hydroxyphenyl)propane (bisphenol-A);

2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane;

2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane;

1,1-bis(4-hydroxyphenyl)cyclohexane;

1,1-bis(3,5-dimethyl-4-hydroxyphenyl)cyclohexane;

1,1-bis(4-hydroxyphenyl)cyclododecane;

1,1-bis(4-hydroxyphenyl)decane;

1,4-bis(4-hydroxyphenyl)butane;

p,p'-dihydroxydiphenyl;

bis(4-hydroxyphenyl)ether; and

4,4'-thiodiphenol.

Other useful dihydric phenols are described, inter alia, in U.S. Pat.Nos. 3,028,365; 2,999,835; 3,148,172; 3,271,368; 2,991,273; 3,271,367;3,280,078; 3,014,891 and 2,999,846, all of which are incorporated hereinby reference.

The carbonate precursors employed in the practice of the instantinvention include the carbonyl halides, the bishaloformates, and thediarylcarbonates. The carbonyl halides include carbonyl bromide,carbonyl chloride, and mixtures thereof. Typical of the diarylcarbonatesare diphenyl carbonate; di(halophenyl) carbonates such asdi(chlorophenyl)carbonate, di(bromophenyl) carbonate,di(trichlorophenyl)carbonate, and di(tribromophenyl)carbonate;di(alkylphenyl)carbonates such as di(tolyl)carbonate; dinaphthylcarbonate; di(halonaphthyl)carbonates; and naphthyl phenyl carbonate.The bishaloformates suitable for use herein include the bishaloformatesof dihydric phenols such as the bischloroformates of hydroquinone andbisphenol-A; the bishaloformates of glycols such as thebischloroformates of ethylene glycol, neopentyl glycol, and polyethyleneglycol.

The polycarbonates of the instant invention contain at least onerecurring structural unit represented by the formula ##STR10## whereinA, R.sup. 1, R.sup. 2, n', n" and y are as defined hereinafore.

The polycarbonates of the instant invention also contain terminal or endgroups represented by the general formula ##STR11## wherein R, R', a, b,W and X are as defined hereinafore.

In a preferred embodiment the instant polymers will contain two moles ofend groups of Formula II per mole of carbonate polymer.

The instant polycarbonates are high molecular weight aromatic carbonatepolymers having an intrinsic viscosity, as determined in chloroform at25° C. of from about 0.3 to about 1.5 dl/gm, preferably from about 0.45to about 1.0 dl/gm. These polycarbonate generally have a weight averagemolecular weight of from about 10,000 to about 200,000, preferably fromabout 20,000 to about 100,000 as measured by gel permeationchromatography.

Another embodiment of the instant invention involves using theendcapping agents of Formula II in conjunction with the conventionalknown endcapping or chain terminating agents such as Chroman I, phenol,and p-tertiarybutylphenol. In such case a statistical mixture ofpolymers containing different terminal groups will be formed. Theamounts of the various terminal groups present will depend on therelative amounts and relative reactivities of the various chainterminating agents used.

Also included with the scope of the instant invention are the highmolecular weight thermoplastic randomly branched polycarbonates Theserandomly branched polycarbonates may be prepared by utilizing a minoramount of a branching agent. These branching agents are well known inthe art and are generally organic polyfunctional aromatic compoundscontaining at least three functional groups which may be hydroxyl,carboxyl, carboxylic anhydride, haloformyl and mixtures thereof. Someillustrative non-limiting examples of these branching agents includetrimellitic anhydride, trimellitic acid, trimellityl trichloride,4-chloroformyl phthalic anhydride, pyrommellitic acid, pyromelliticdianhydride, trimesic acid, and benzophenonetetra carboxylic acid Someother useful branching agents are disclosed in U.S. Pat. Nos. 3,635,895;4,001,184 and 4,204,047, all of which are incorporated herein byreference.

A convenient method of preparing the instant polycarbonate is theinterfacial polymerization process. This process involves the coreactionof (i) at least one dihydric phenol, (ii) a carbonate precursor such asphosgene, and (iii) an endcapping amount, i.e., from about 0.1 to about10 mole percent, based on the moles of dihydric phenol used, of at leastone endcapping agent of Formula II. The reaction is carried out in thepresence of two different liquid phases which are immiscible with eachother and which constitute two solvent media. Normally one of theseliquid phases is an alkaline aqueous medium while the other liquid phaseis an organic medium such as methylene chloride. Also present arecatalysts which are conventionally used in the interfacialpolymerization process of forming polycarbonates. These catalystsinclude, but are not limited to, tertiary amines such as triethylamine,quaternary ammonium compounds, and quaternary phosphonium compounds.

Also included within the scope of the instant invention are thecopolyestercarbonate resins which are described, inter alia, in U.S.Pat. Nos. 3,169,121 and 4,465,820, which are incorporated herein byreference. These copolyestercarbonates may be prepared by reacting (i)at least one dihydric phenol, (ii) a carbonate precursor, (iii) at leastone compound of Formula II, and (iv) at least one ester precursor.

The carbonate polymers of the instant invention may optionally haveadmixed therewith the commonly known and used additives such asantioxidants, inert fillers such as clay, mica, talc, and glass; impactmodifiers; ultraviolet radiation absorbers such as benzophenones;hydrolytic stabilizers such as the epoxides taught in U.S. Pat. Nos.3,489,716; 4,138, 379 and 3,839,247, all of which are incorporatedherein by reference; color stabilizers such as the organophosphitesdisclosed in U.S. Pat. Nos. 3,305,520 and 4,118,370, both of which areincorporated herein by reference; and flame retardant agents.

At least one of the chain terminating agents is a compound of FormulaII. The compound of Formula II is prepared by the simple imidization asshown below wherein the compound of Formula V is reacted with thecompound of Formula VI. ##STR12## wherein R, R', a, b and Y are aspreviously defined.

The amine phenols or amine carboxylic acids or derivatives andsubstituted molecules of Formula VI are well known in the art. Thecompounds of Formula V are simply prepared by the Diels-Alder dienedienophile adduct reaction between compounds of Formula VII and FormulaVIII shown below. ##STR13## wherein W, R' and a are as defined above.Preferably W is CHR or CR.sub. 2, R" is chloro or alkyl of one to threecarbon atoms, inclusive, and a is zero or one, more preferably one. Thecompound of Formula VIII , a cyclic --B unsaturated carboxylic acidanhydride such as maleic anhydride, is below. ##STR14##

An alternative reaction scheme is to react the compound of Formula VIIIwith the compound of Formula VI to form the imide which is then reactedwith the compound of Formula VII to form the compound of Formula II. Asused above and in the claims, alkyl is normal or branched hydrocarbon ofone to six carbon atoms, inclusive, aryl is phenyl or napthyl andhalogen is fluoro, chloro or bormo.

The compound of Formula II is then used as a chain terminating agent inthe usual preparation of polycarbonate as one of ordinary skill in theart would use any phenol such as phenol or paratertiary butyl phenol. Ingeneral the chain terminating agent of Formula II should be present infrom about 1.0 to about 10.0 mole percent based upon the moles of thedihydric phenol present in the polycarbonate.

The finally prepared polycarbonate endcap with the compound of FormulaII is non-toxic, easy to handle, and is non-reactive at ordinarytemperatures. However, at temperatures of about 250° to about 350° C.,the norbornene like portion of the compound becomes labile and is lostfrom the molecule as cyclic diene, thereby leaving a maleimide endgroup, shown below ##STR15## wherein R, b and Y are hereinafore defined.Such a temperature is commonly achieved during extrusion of thepolycarbonate. Therefore during extrusion processes the chain terminatedpolycarbonate of this invention becomes reactive and can react withitself or with other materials providing reactive sites for themaleimide. Examples of such materials include polyolefins and styrenicmolecules such as acrylonitrile, butadiene-styrenes. Under thesecircumstances, new copolymers will be formed from the covalent reactionswhich occur between the maleimide and the active site of the otherpolymer.

Below are examples of the invention. These examples are intended toillustrate rather than narrow the general inventive concept of theinvention.

EXAMPLE 1

PREPARATION OF NORBORNENE-HYDROXY PHENOL IMIDES

a. Norbornene dicarboxylic anhydride, 180g (1.1m) was dissolved in 250mlchlorobenzene in a flask fitted with a mechanical stirrer and anapparatus to remove water. m-Amino phenol, 120.0g (1.1m) was added tothe solution with stirring. Dimethylamino pyridine (1.0g) was added ascatalyst. The reaction was heated to reflux under nitrogen with removalof 20 ml water, and 50 ml solvent. The reaction was then cooled to 40°C. The product crystallized from solution and was isolated by hotfiltration. The crude product was washed with isopropanol. Yield 262.5g,94%, of a tan crystalline product. A second crop of darker orange solid,5.2g, was discarded. mp 194-208° C. (DSC peak at 200° C). IR(KBr) 3380,1760, 1690, 1610, 1460, 1390, 1270, 1180 cm-1. CNMR 176.8, 157.2, 134.4,128.1, 123.5, 115.3, 51.6, 45.2, 44.8, ppm d.sub. 6-DMSO.

b. The adduct of p-amino phenol and norbornene dicarboxylic anhydridewas prepared in a similar fashion yielding 91% of a fluffy powder, mp245-249° C. IR(KBr) 3380, 1770, 1690, 1520, 1390, 1280, 1180 cm-1. CNMR176.5, 157.7, 134.4, 133.3, 129.4, 117.6, 115.3, 114.2, 51.7, 45.3,44.8, ppm d.sub. 6-DMSO.

The norbornene imides were insoluble in methylene chloride, water andacetic acid and soluble in sodium hydroxide and hot isopropanol.Materials were used in polymerization with no further purification.

EXAMPLE 2

A representative polymerization is described below. A five necked resinkettle was charged with 2.0L methylene chloride, 1.5L deionized water,500g (2.19m) bisphenol-A, 13.9 (0.055m) m-amino phenol norbornene imidefrom Example 1a and 3.0 ml triethylamine. The solution was phosgenatedat 2.0 g/min for 2 hr. pH 9.5-10.5 was maintained by addition of 50%aqueous NaOH. After phosgenation the crude aqueous layer showed noprecipitate upon acidification. The organic layer was washed once withwater, once with 5% aqueous HCL and 3 times again with water. Polymerwas isolated by addition to steam heated water in a large blender. Allintrinsic viscosities (IV) were measured in chloroform. GPC results arerelative to polystyrene standards.

                  TABLE I                                                         ______________________________________                                        IMIDE PHENOL CAPPED POLYCARBONATES                                                  MOLE %                                                                  SAM-  PHENOL*                          IV   Tg                                PLE   ENDCAPPER   Mw       Mn    DISP  dl/g °C.                        ______________________________________                                        A     1.0         122800   44200 2.8   0.846                                                                              156                               B     1.6         67900    28000 2.4   0.644                                                                              154                               C     2.5         79000    20300 3.9   0.711                                                                              152                               D     2.5         66300    20000 3.3   0.699                                                                              153                               E     2.5         74700    22200 3.4   0.699                                                                              153                               ______________________________________                                         *Mole % based on BPA                                                     

In most cases GPC analysis of these polymers showed a widepolydispersity due to a low molecular weight tail. However comparison ofa hot water, methanol or acetone precipitated polymer showed similarimide content. The polymers formed a tough flexible transparent filmfrom methylene chloride solution.

EXAMPLE 3

Combined samples C, D and E were heated at 260° C., 32 rpm for 20minutes in a steel mixing bowl. The fluffy powder took 13 minutes toload into the mixing bowl.

    ______________________________________                                        TIME, MINUTES    IV dl/g                                                      (AFTER LOADING)  (CHCl3) at 25° C.                                     ______________________________________                                         1               0.708                                                         3               0.710                                                         5               0.705                                                        10               0.714                                                        15               0.714                                                        20               0.735                                                        ______________________________________                                    

The increase in I.V. demonstrates that the polymers are losingcyclopentadiene and crosslinking at the maleimide bond.

EXAMPLE 4

a. Reaction was similar to a standard interfacial polymerization with200 ml methylene chloride, 300 ml deionized water, 12.5g bisphenol-A(0.061lm), 7.0g norborne parahydroxy phenolimide from Example 1b(0.0276m) and 0.5 ml triethylamine. COCl.sub. 2 was added at 1.0 g/minfor 14 minutes at pH 10-11. After separation from the water layer themethylene chloride layer was washed once with water, once with 5% HCLand four times with water. The solution was dried over anhydrouspotassium carbonate and evaporated to dryness. Yield 17.2g. IR spectrashowed very little hydroxy absorbance, carbonyl region showed peaks at1770, 1715 cm-1. IV=0.175 dl/g, Tg 101° C., CNMR 176.3, 151.5, 150.5,148.6, 148.1, 134.5, 133.2, 129.7, 127.7, 125.1, 120.9, 120.6, 119.9,51.7 45.5, 44.9, 42.1, 30.4 ppm d.sub. 6 -DMSO.

The polymer showed 30 wt. % imide end groups (83% incorporation). Imideend group incorporation was also confirmed by carbon-13 NMR.

Analysis of the polymer by thermal gravimetric analysis (TGA) showed aweight loss of 6.9% between 260-360° C. This weight loss corresponds tothe loss of cyclopentadiene liberating the reactive maleimide end group.

b. The meta phenol imide of Example 1a was used to prepare oligomers bya similar route as above using 5.0g m-phenolimide (0.02m) and 8.9g BPA(0.039m). Yield 13.5g. IR spectra was as above. CNMR 176.5, 150.0,148.6, 148.2, 148.1, 134.5, 130.2, 128.3, 127.7, 121.7, 120.6, 51.7,45.4, 44.8, 42.1, 30.4 ppm d.sub. 6 -DMSO. IV=0.108 dl/g, Tg 108° C.

The polymer showed 32 wt. % imide end groups (89% incorporation). Imidephenol end group incorporation was confirmed by carbon-13 NMR.

TGA analysis showed an 8.4% weight loss between 260°-360° C.(Theoretical weight loss of cyclopentadiene 8.9%).

What is claimed is:
 1. An aromatic polycarbonate containing at least oneterminal group of the formula ##STR16## wherein R is alkyl, aryl orhalogen; b is zero or an integer of one to four; Y is ##STR17## whereineach R.sub. 2 is independent and hydrogen or alkyl of one to six carbonatoms, inclusive; aryl ##STR18##
 2. the polycarbonate in accordance withclaim 1 wherein b is zero.
 3. The polycarbonate in accordance with claim1 wherey Y is --0.
 4. The polycarbonate in accordance with claim 3wherein b is zero and Y is meta to the nitrogen.
 5. The polycarbonate inaccordance with claim 3 wherein b is zero and X is para to the nitrogen.